TRANSACTIONS OF THE SECTIONS. I/ 



An Account of some Indications of the Anemometers erected at Plymouth 

 and Birmingham. By Follett Osler. 



An anemometer and rain-gauge, similar (said Mr. Osier) to the one 

 that I constructed about three years ago, and which has, since that period, 

 been at work at the Birmingham Philosophical Institution, was erected 

 at Plymouth, a few months ago, by order of the British Association, and 

 placed under the supeiintendence of Mr. Snow Harris. Having just re- 

 ceived the registers of this instrument, I shall take a cursory review of a 

 few of them, in conjunction with those obtained at Birmingham. I shall 

 confine my remarks entirely to the direction of the wind as registered, 

 and not attempt on the present occasion to connect any barometric or 

 thermometric observations with these. As it would not be possible to 

 illustrate more than a few of these observations, I have selected those 

 only in which the wind has been tolerably steady and strong, as being the 

 best mode of giving a correct idea of the nature and value of these ob- 

 servations. 



On the 17th of November, 1838, a steady wind set in at Ply- 

 mouth about 8 o'clock a.m., from the S. by E., and continued until 

 8 o'clock on the following evening, a period of thirty-six hours. 

 The steadiness of this current at Plymouth was very remarkable : 

 during the first part of the time there was almost a perfect calm in 

 Birmingham; however, by 10 o'clock in the evening, that is to say, 

 fourteen hours after the current from the S. by E. had set in at Ply- 

 mouth, a slight wind was felt at Birmingham from the north ; in three 

 hours more, that is, by 1 a.m. on the 18th of November, it became 

 E.N.E., and finally set in a strong gale from N.E. by N., which lasted 

 the remainder of the day. It is a singular fact, that as the gale in- 

 creased in force at Birmingham it declined at Plymouth ; this was 

 towards the middle of the day ; in the evening the contrary took 

 place. The rush of air from the S. by E. at Plymouth continuing for 

 such a length of time previous to any wind being felt at Birmingham, 

 clearly shows that this must have been the main current ; and it seems 

 highly probable that the atmosphere for some distance north and south 

 of this current was gradually affected, and eventually drawn into it. 

 The state of the wind on the next day (November 19th) very much 

 confirms this view of the subject : the current by that time became due 

 E. at Plymouth, and N.E. at Birmingham. On the 20th there was but 

 little wind at either place, and the directions then became the same in 

 both places. During a considerable portion of the time much rain fell, 

 about '16 of an inch in Birmingham, and 1*32 at Plymouth; the two 

 principal falls in Plymouth preceding those in Birmingham by about 

 four hours. 



On March 28 a strong wind set in from the west at Plymouth, 

 which continued the whole day. At Birmingham the wind was S.S.W. 

 when this gale commenced ; but alter continuing in that direction 

 about twelve hours, it moved gradually round to the west, and finally 

 to the W.N.W. During the time of this change, the strength of 

 the wind at Plvmouth increased considerably, though it did not alter 



1839. ' c 



